Water softeners: do you need one, and what to know first
A water softener is a choice about comfort and upkeep, not a health need. Health Canada says a health-based value for hardness is not warranted, and Ontario lists hardness as “not a health hazard”.[1][2] Whether a softener is worth it depends on how hard your water is and what bothers you: scale in your water heater and on taps, deposits on dishes, stiff laundry. Check your hardness figure first. And know that a salt-based softener adds sodium to your water, which matters if you limit salt or have young children.
On this page
Do you need a water softener?
Health Canada describes hardness this way: water above 200 mg/L is “considered poor but have been tolerated by consumers”, and water above 500 mg/L is “unacceptable for many domestic purposes and may require softening”.[1] It adds that people may get used to harder water, and that what people accept varies with local conditions.
So start with your number:
| Your water | How to find your hardness | Read more |
|---|---|---|
| City water | Your city’s or region’s water report | Water hardness by city |
| Private well | A test at a licensed lab. Health Canada encourages well owners to have their water tested for hardness. | Well water testing |
Source: Health Canada, Operational Parameters guideline.[1]
Softener settings and sizes often use grains per gallon. Check which gallon your figure uses before you compare; our hardness page explains.
How does a water softener work?
Most softeners use ion exchange. Water flows through a tank of small resin beads coated with sodium or potassium. The calcium and magnesium that make water hard trade places with the sodium or potassium, which is why softened water has more salt in it. When the beads are full of hardness, the softener recharges them with salt from its brine tank and rinses the hardness down the drain.[3]
Health Canada calls water softeners the best available technology for reducing hardness at home.[1] Ontario notes what they don’t do: softeners are unsuitable for removing microbes or most chemicals.[2]
Softened water and drinking water
A softener that uses sodium salt adds sodium to your water, and the harder your water, the more it adds.[1] Health Canada’s figures:
| Hardness before softening (mg/L) | Sodium added (mg/L) |
|---|---|
| 100 | 46 |
| 200 | 92 |
| 500 | 230 |
Source: Health Canada, Operational Parameters guideline, Appendix E (softener using sodium chloride).[1]
What Health Canada advises:
- When you use a softener, have the tap you drink from most, usually the kitchen tap, bypass it.[1]
- Generally, children under 8 should not drink water containing sodium from a softener, because they may go over the recommended upper limit of 1.5 to 1.9 g of sodium a day.
- If you’re on a sodium-restricted diet, talk to your doctor.
- Softening with potassium instead may add potassium at levels that can affect some people.
The Region of Waterloo and City of Guelph note that potassium chloride works in the same way as softener salt for people concerned about sodium; check your owner’s manual before switching.[3]
In rare cases, water harder than 750 mg/L could give more calcium than Health Canada’s health-based value for calcium, and Health Canada says to find another drinking water source.[1]
What to look for in a water softener
- Certification to NSF/ANSI Standard 44 (Residential Cation Exchange Water Softeners). To be certified for hardness, a softener must bring water from 342 mg/L down to below 17.1 mg/L.[1] The Region of Waterloo also suggests an efficient softener certified to NSF 44.[4]
- The right standard number. Ontario says equipment with the NSF certified mark has been checked for performance and the factory is inspected every year, but there are several NSF standards, so check the number matches what you need.[2]
- How it regenerates. Demand-initiated softeners measure your water use and regenerate only when needed; timer models regenerate on a schedule and can waste salt and water.[3]
For lead, see water filters for lead.
What size water softener do I need?
Softeners are rated by how many grains of hardness they can remove before they regenerate. The Region of Waterloo and City of Guelph size one this way:
- Work out your household’s daily water use, not counting outdoor watering.[5] Your fall or winter water bill gives the most accurate figure.
- Find your hardness in grains per US gallon (one grain is 17.1 mg/L).
- Multiply the two. That’s how many grains your softener must remove each day.
- Multiply by seven. Most suppliers suggest a softener that can go about a week between regenerations.
On a well, have iron tested along with hardness: iron adds to the hardness rating a softener must handle.[5] When you get a quote, ask which hardness figure it uses.
Water softener salt and upkeep
- Add salt and dispose of the salty rinse water. Ontario lists both as ongoing needs.[2]
- Set the softener to your actual hardness, so it uses only the salt it needs, and check that it isn’t leaking or regenerating too often.[4]
- Choose your salt. Rock salt contains more material that doesn’t dissolve; solar and evaporated salt keep a softener cleaner.[3]
- Consider softening only your hot water. The Region of Waterloo says this uses less water and salt, and still protects your water heater, since scale builds up faster in hot water.[6]
- Test now and then. Health Canada recommends sending samples of the water going into and coming out of a home treatment unit to an accredited lab, and maintaining it as the manufacturer says.[1]
The Region of Waterloo also notes that the salty rinse water from softeners ends up in waterways, where it can harm freshwater plants and animals.[4]
Salt-free softeners
Most salt-free units don’t soften water. They don’t remove calcium and magnesium; they change them so they’re less likely to form scale.[3] A study the two cite found that all four types tested prevented scale on water heater elements, with varied results, and that one type (template or nucleation assisted crystallization) cut scale on water heater elements by about 90 percent, matching salt-based softeners.
In the Region and City’s own study, 18 households tried salt-free units for a year and 13 kept them.[3] Those who didn’t mentioned film left on dishes and not knowing whether the unit was working. The certification standard Health Canada lists for softeners, NSF/ANSI 44, covers ion exchange softeners, so ask any seller which standard a salt-free unit is certified to.[1]
Installation, cost and rentals
We don’t list prices. Ontario suggests weighing the full cost of any home treatment system: purchase and installation, replacements, electricity and ongoing maintenance.[2]
Before you sign a purchase or rental contract, Ontario suggests asking these questions and getting the answers in writing:[7]
- How long is the contract?
- When and how can you get out of it, and what does cancelling cost?
- Will it renew automatically without your consent?
- Are there fees for removing old equipment, installing new equipment, or anything else?
- If you sell your home, do you have to transfer the contract or pay a fee?
- What warranty comes with it?
Water softeners are among the products that can’t be sold at your door unless you asked the business to come.[7] See “free water test” offers for Ontario’s rules. This is general information, not legal advice.
On a well
Ontario’s well treatment guide lists a softener for hardness, and also for low levels of manganese (under 0.1 ppm).[2] Before you choose, test your water.[1] For a well with a sodium softener, Health Canada recommends a separate supply for drinking and cooking. See well water testing.
Is it healthier to drink hard or softened water?
Health Canada says a health-based value for hardness is not warranted.[1] Softened water has added sodium, which is why Health Canada recommends a drinking tap that bypasses the softener and advises against softened water for children under 8.
Sources
- Health Canada, Guidelines for Canadian Drinking Water Quality: Operational Parameters. Checked . ↩︎
- Government of Ontario, Testing and treating private water wells. Checked . ↩︎
- Water Softener Facts (Region of Waterloo and City of Guelph), How Softeners Work. Checked . ↩︎
- Region of Waterloo, Hard Water Treatment. Checked . ↩︎
- Water Softener Facts (Region of Waterloo and City of Guelph), Softener Buyers Guide. Checked . ↩︎
- Region of Waterloo, Redirecting plumbing to soften hot water only. Checked . ↩︎
- Government of Ontario, Door-to-door sales and home service contracts. Checked . ↩︎